Sex pheromone of the California red scale, Aonidiella aurantii

Abstract

THE California red scale, Aonidiella aurantii (Maskell), is the most important citrus pest in Australia, California and the Mediterranean countries. It has been found¹ that red scale females attract males with a sex pheromone, and preliminary studies² have indicated that a branched acetate may be involved. Much interest has been generated in the identification of this pheromone because no other Homopteran sex pheromone has been reported and because the synthetic pheromone has immediate application in replacing the commercial virgin female traps used extensively in monitoring this pest. The sex pheromone reported here consists of two novel components, 3-methyl-6-isopropenyl-9-decen-1-yl acetate (I) and (Z)-3-methyl-6-isopropenyl-3, 9-decadien-l-yl acetate (II). The norsesquiterpene structures represent interesting biosynthetic pathways since they do not merely involve head-to-tail coupling of the isoprenoid units. These compounds also present a synthetic challenge because (I) possesses two asymmetric centers and (II) possesses one asymmetric centre. (Fig. 1).